The average life span of strawberry leaves is 60-80 days, and the effective leaf age is 30-60 days. Old leaves over 60 days consume more nutrients than they produce, so they can be removed. The wound healed in 24 hours at seedling stage and 72 hours after picking leaves at flowering and fruiting stage, so the disease was serious at this stage. Therefore, after picking leaves, it is necessary to spray chemicals in time, such as mancozeb, zineb and chlorothalonil.